Solid state welding
This is a welding technique that does not melt the metal to make the weld. This type of welding is normally done to make electrical connections out of aluminum or copper. This is almost similar to resistance welding but instead of heat that is used to melt the metals, the energy is provided in form of vibrations. The metals pieces in high pressure join with each other under the influence of the vibrations. When plastic materials are joined like this, it should be kept in mind that both the materials should have the same melting points. Also, when joining plastics, the vibrations are introduced vertically under high pressure. Examples of solid state welding can be ultrasonic welding and explosion welding. With the metals not welding under heat, there is no wastage of metals and also the weld is much cleaner without any marks or deformation in the line of weld as the other forms of welding.